<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .c1{
            color: red;
        }

        .c2{
            font-size: 50px;
        }
    </style>
</head>
<body>
    <div class="c1 c2">
        div
    </div>
</body>
</html>